From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE56DC388F9 for ; Wed, 11 Nov 2020 10:54:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 865542067D for ; Wed, 11 Nov 2020 10:54:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725903AbgKKKyI (ORCPT ); Wed, 11 Nov 2020 05:54:08 -0500 Received: from mx2.suse.de ([195.135.220.15]:43246 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725895AbgKKKyH (ORCPT ); Wed, 11 Nov 2020 05:54:07 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E6455ABDE; Wed, 11 Nov 2020 10:54:05 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 7F4971E130B; Wed, 11 Nov 2020 11:54:05 +0100 (CET) Date: Wed, 11 Nov 2020 11:54:05 +0100 From: Jan Kara To: Chengguang Xu Cc: Jan Kara , miklos , amir73il , linux-unionfs , linux-fsdevel Subject: Re: [RFC PATCH v3 07/10] ovl: implement overlayfs' ->write_inode operation Message-ID: <20201111105405.GB28132@quack2.suse.cz> References: <20201108140307.1385745-1-cgxu519@mykernel.net> <20201108140307.1385745-8-cgxu519@mykernel.net> <20201110134551.GA28132@quack2.suse.cz> <175b2b6ef3d.11f9425843834.4407023737229017217@mykernel.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <175b2b6ef3d.11f9425843834.4407023737229017217@mykernel.net> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Tue 10-11-20 23:12:14, Chengguang Xu wrote: > ---- 在 星期二, 2020-11-10 21:45:51 Jan Kara 撰写 ---- > > On Sun 08-11-20 22:03:04, Chengguang Xu wrote: > > > +static int ovl_write_inode(struct inode *inode, > > > + struct writeback_control *wbc) > > > +{ > > > + struct ovl_fs *ofs = inode->i_sb->s_fs_info; > > > + struct inode *upper = ovl_inode_upper(inode); > > > + unsigned long iflag = 0; > > > + int ret = 0; > > > + > > > + if (!upper) > > > + return 0; > > > + > > > + if (!ovl_should_sync(ofs)) > > > + return 0; > > > + > > > + if (upper->i_sb->s_op->write_inode) > > > + ret = upper->i_sb->s_op->write_inode(inode, wbc); > > > + > > > + iflag |= upper->i_state & I_DIRTY_ALL; > > > + > > > + if (mapping_writably_mapped(upper->i_mapping) || > > > + mapping_tagged(upper->i_mapping, PAGECACHE_TAG_WRITEBACK)) > > > + iflag |= I_DIRTY_PAGES; > > > + > > > + if (iflag) > > > + ovl_mark_inode_dirty(inode); > > > > I think you didn't incorporate feedback we were speaking about in the last > > version of the series. May comment in [1] still applies - you can miss > > inodes dirtied through mmap when you decide to clean the inode here. So > > IMHO you need something like: > > > > if (inode_is_open_for_write(inode)) > > ovl_mark_inode_dirty(inode); > > > > here to keep inode dirty while it is open for write (and not based on upper > > inode state which is unreliable). > > Hi Jan, > > I not only checked upper inode state but also checked upper inode > mmap(shared) state using mapping_writably_mapped(upper->i_mapping). > Maybe it's better to move i_state check after mmap check but isn't above > checks enough for mmapped file? Ah, sorry, I'm blind! I missed the mapping_writably_mapped() check. Thanks for explanation. Honza -- Jan Kara SUSE Labs, CR